1. Field of the Invention
The present invention relates to an optical element, and in particular to an optical element which can enlarge light emitting angle of light.
2. Description of Prior Art
A light emitting diode (LED) is a kind of semiconductor device, which exploits the property of direct-bandgap semiconductor material to convert electric energy into light energy efficiently and has the advantages of long service time, high stability and low power consumption and is developed to replace the traditional non-directivity light tube and incandescent lamp.
The LED is a point-like light source and has high directivity so that the lighting surface of the LED is narrower than that of the traditional light sources, and the luminous intensity of the LED is gradually reduced while the lighting distance is increased, so that the LED is more suitable for providing short-distance and small area lighting fixture, such as table lamp.
In order to solve the mentioned problem, many manufacturers assemble and arrange multiple LEDs to centralize light for solving the problem of narrow lighting range. However, the required power for driving the LEDs is increased when the number of the LEDs is increased, therefore, the effect of saving energy cannot be achieved. Moreover, the price of LED lamp is far higher than the traditional light source so as to reduce the will of using LED lamp.